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STEREO Sterile neutrinos search at the ILL reactor An update for the ENIGMASS plenary meeting Nov.2013 LPSC : S. Kox, J. Lamblin, F. Montanet, J.S Réal,

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Presentation on theme: "STEREO Sterile neutrinos search at the ILL reactor An update for the ENIGMASS plenary meeting Nov.2013 LPSC : S. Kox, J. Lamblin, F. Montanet, J.S Réal,"— Presentation transcript:

1 STEREO Sterile neutrinos search at the ILL reactor An update for the ENIGMASS plenary meeting Nov.2013 LPSC : S. Kox, J. Lamblin, F. Montanet, J.S Réal, A. Stutz, S.Zsoldos(PhD), postdoc Enigmass under selection LAPP : P. Del Amo Sanchez, H. Pessard, L.Manzanillas (PhD)

2 Scientific Context 11/6/2013 Labex ENIGMASS plenary meeting2

3 Scientific Context Revisiting 19 experiments at L ≤ 100 m – Normalization accounting for core composition – Dealing with correlations between experiments Deficit : R= ±  RAA is a 3 σ effect Mention et al Recent update accounting for km-baseline expts and new theta13 from DayaBay Deficit : R= ±  RAA is still significant 2.7 σ effect. + other hints : Ga source calibration + etc… Possible explanations: – Bad luck with Statistics? – Common bias in flux prediction? – Common experimental bias? Or new physics at short distance? 11/6/2013 Labex ENIGMASS plenary meeting3 arXiv:

4 Science case for a 4 th sterile neutrino 11/6/2013 Labex ENIGMASS plenary meeting4

5 Science case for a 4 th sterile neutrino A new sterile neutrino with small mixing and mass O(eV). "Sterile" means no weak interaction coupling !  "Visible" only through its mixing with active neutrinos 11/6/2013 Labex ENIGMASS plenary meeting5 G. Mention et al. Phys Rev D (2011)

6 STEREO at the forefront The RAA has triggered a strong worldwide activity around the search for sterile neutrinos. (white paper arXiv: v1 [hep-ph] 18 Apr 2012) Numerous projects in preparation, some very challenging. STEREO is based on a well proven technology and is aiming at starting data taking early The ILL research nuclear reactor is an ideal place for a short baseline experiment : dense core, as close as 8m from the core, stable composition, frequent reactor off, … A target of opportunity is offered with a long reactor shutdown period  Installation completed before end of 2014 !!! 11/6/2013 Labex ENIGMASS plenary meeting6

7 What makes STEREO the first of a new kind 11/6/2013 Labex ENIGMASS plenary meeting7 A robust and unambiguous analysis of the oscillation: "Shape and Normalization" – Observe energy spectrum deformation – Evolution of the phase with distance – Less dependent on the flux predictions Requirements: – A good energy resolution – A reduced smearing with distance (source + detector) – Critical requirement : background effects to be fully mastered Observed/Expected

8 STEREO detection principle 11/6/2013 Labex ENIGMASS plenary meeting8

9 STEREO detection principle 3.30 m 2.30 m 2.50 m

10 STEREO detection principle Active shielding : – outer crown "gamma-catcher" acting as an active shielding – Cherenkov veto counter on top Passive shielding all around the target: – 10 to 20cm lead – 15cm to 30cm borated PE External shielding: – to reduce gamma-ray and thermal & fast neutron flux in the casemate. μ μ n th nfnf PEHD Veto μ PSD γ

11 STEREO discovery potential 300 days reactor ON days OFF - S/B = /6/2013 Labex ENIGMASS plenary meeting11 Shape analysis Shape and rate analysis STEREO discovery potential depends on a tight installation planning and on background rejection. Expected signal 480 ν/ day Challenge : S/B > 1.5 (≈ ILL-1)

12 The Collaboration, the Work Packages 11/6/2013 Labex ENIGMASS plenary meeting12

13 Funding 990 k€ ANR grant, Oct 2013 – March 2017, shared between CEA and IN2P3 labs. Part of shielding budget and a 2 years postdoc were cut + extra lead and B4C shielding needed. 50 k€ Irfu funds for prototype cell. AGIR fund from UJF (pôle SMINGUE) 10 k€ for electronics prototyping. Liquids and PMTs to be provided by MPIKH. Beam stopper and site reconfiguration by ILL External shielding mechanics by Univ. of Casablanca 11/6/2013 Labex ENIGMASS plenary meeting13

14 Planning 11/6/2013 Labex ENIGMASS plenary meeting14

15 Recent actions Background measurement campaigns – Localizing sources – Defining action – Input to detector simulation Improving the experiment – H7 plug replacement, 6 Li suppression upstream – Reinforced H7/STEREO casemate – H13 (neighboring casemate, source of most of the fast neutrons and gamma-rays): shielding to be reinforced 11/6/2013 Labex ENIGMASS plenary meeting15 Additional shielding installed during the ILL long shutdown Benefit from the first cycles to validate and optimize the external shielding before the detector

16 Recent actions Designing and proof-testing the detector and shielding support 11/6/2013 Labex ENIGMASS plenary meeting16

17 Recent actions Calibration systems: LED and Radioactive sources – Energy resolution is critical – Absolute calibration (with  and n sources) – Liquid optical properties, linearity studies, cross-calibration and fast system tests with LEDs) All systems are currently at the conceptual design level. 11/6/2013 Labex ENIGMASS plenary meeting17

18 Recent actions Full size cell prototype under Will allow – tests of PSD on different scintillators, – calibration system tests, – FE electronics tests – etc… 11/6/2013 Labex ENIGMASS plenary meeting18

19 Recent actions LPSC Custom front-end + trigger + DAQ electronics based on FPGA. Signal digitization with signal analysis functions: Qtot, Qtail, full trace readout, timming, etc… Trigger and event building LED calibration driver 11/6/2013 Labex ENIGMASS plenary meeting19 Current prototype : Front end board where a part of the FPGA is used to simulate the trigger board. Currently routing -> 20/10. Manufacturing and cabling -> 15/11

20 Recent actions VETO counter: Sign cosmic-rays induced background in stereo i.e. fast neutron induced by muons in shielding Large signal from minimum ionizing particle in stereo Requirements Fully efficient to cosmic muons, Quasi insensitive to background  -rays Made of non-flammable material  Water Cherenkov Prototype : Almost full size tank 3X2X0.25 m3 14 PMTs (5” XP4572, borosilicate) Complete coverage CR telescope. Tyvek diffuser being installed 11/6/2013 Labex ENIGMASS plenary meeting20

21 Conclusions – STEREO aims at a precise measurement at less than 10m from the compact core of the ILL research reactor. – A distortion of the energy spectrum as a function of the distance to the core will provide a clear signature for a new oscillation, independently from flux calculations. – The achievable sensitivity and the installation and data taking schedule will offer a high discovery potential. – The challenging times schedule will require important efforts and support. The Enigmass postdoc position currently under selection will be essential to the success of the project and will have a good visibility. 11/6/2013 Labex ENIGMASS plenary meeting21

22 BACKUP SLIDES 11/6/2013 Labex ENIGMASS plenary meeting22

23 PhD - Postdocs  LPSC-IN2P3: 1 postdoc funded by ENIGMASS 1 PhD student: Stéphane Zsoldos  LAPP-IN2P3: 1 postdoc funded by ANR+IN2P3 (?) 1 PhD student: Luis Manzanillas  CEA-Irfu 1 postdoc funded by ANR+Eurotalents (?) 1 PhD student: Maxime Pequignot  MPIK-Heidelberg 1 postdoc : Antoine Collin 1 PhD student  ILL 1 PhD?  Univ. Casablanca 1 PhD? 11/6/2013 Labex ENIGMASS plenary meeting23

24 Expected performances 11/6/2013 Labex ENIGMASS plenary meeting24 Signal attendu 480 ν/ jrs Challenge : S/B > 1.5 (≈ ILL-1) Phys. Rev. D Puissance du réacteur57 MW σ ( 235 U) /fission cm 2 Distance moyenne au cœur10 m Nombre de protons cibles1, Seuil Evis à 2 MeV ( E ν > 2.8 MeV)81 % Efficacité neutron (Edep > 5 MeV)64 % Temps mort5 % 2 MeV10 % δL evt by evt32 cm

25 Backgrounds 11/6/2013 Labex ENIGMASS plenary meeting25 μ μ n th nfnf PEH D Veto μ PSD γ

26 Implantation sur site Contraintes d’installation – Sécurité sismique – Sécurité incendie – Dossier ASN à déposer fin 2013 – Travail en cours avec expert incendie et ingénieure de sécurité ILL Modification du détecteur par rapport au projet initial – Distance STEREO/réacteur : 10 m – Largeur de la cible réduite de 1.1 à 0.9 m – 6 cellules au lieu de 5 11/6/2013 Labex ENIGMASS plenary meeting26

27 STEREO discovery potential 11/6/2013 Labex ENIGMASS plenary meeting27

28 STEREO discovery potential 11/6/2013 Labex ENIGMASS plenary meeting28 Stereo discovery potential depends on tight installation planning and background rejection.

29 STEREO discovery potential 300 days reactor ON days OFF - S/B = /6/2013 Labex ENIGMASS plenary meeting29 Systematic errors Fission spectrum 0.7 -> 4 % Weak magnetism (E-1.0)*1.0%/MeV Evt/evt distance res δL = 32 cm Source energy calibration 2.0 % Monitoring 1% Normalization systematic errors 3.5% N p 0.5% Spill in Spill out 1% Detection efficiency 2% Thermal power 2.0 % Fission spectrum 1.8 % Shape analysis Shape and rate analysis

30 STEREO discovery potential 11/6/2013 Labex ENIGMASS plenary meeting30

31 STEREO discovery potential 11/6/2013 Labex ENIGMASS plenary meeting31 Stereo discovery potential depends on tight installation planning and background rejection.

32 STEREO discovery potential 300 days reactor ON days OFF - S/B = /6/2013 Labex ENIGMASS plenary meeting32 Systematic errors Fission spectrum 0.7 -> 4 % Weak magnetism (E-1.0)*1.0%/MeV Evt/evt distance res δL = 32 cm Source energy calibration 2.0 % Monitoring 1% Normalization systematic errors 3.5% N p 0.5% Spill in Spill out 1% Detection efficiency 2% Thermal power 2.0 % Fission spectrum 1.8 % Shape analysis Shape and rate analysis STEREO discovery potential depends on a tight installation planning and on background rejection.

33 Recent actions Many interactions with ILL to prepare the experiment environment (H7 plug modifications, 6 Li removal, H13/IN20 frontend shielding etc…) In situ background measurements and identification of background sources. Optimizing detector geometry with full detailed simulation. Simulating background effects, optimizing shielding. Need for a factor ?? reduction. Single cell prototype at Saclay under construction. Front end and acquisition electronics prototype at LPSC. Optimizing liquid scintillator at MPIKH. VETO prototype at LPSC. Structural design of shieldings and supports at LAPP. Designing calibration system (LED at LPSC, sources at LAPP). 11/6/2013 Labex ENIGMASS plenary meeting33

34 ILL schedule 11/6/2013 Labex ENIGMASS plenary meeting34 Feb H13 casemate Oct.-Nov Decommissioning of GAMS5 H7/STEREO casemate 1st half May 2014 H7 plug 1st half Jun H7/STEREO casemate Sequential background tests: June-July 2014: in PN3 with H7 plug + external shielding. Sept. 2014: inside Stereo shielding. Nov. 2014: start detector commissioning. Oct 2014 Detector installation

35 Calendrier 11/6/2013 Labex ENIGMASS plenary meeting35 – Aout mi juin 2014 : Grand arrêt réacteur de 10 mois Remplacement bouchon-collimateur Couverture B4C des casemates PN3 et IN20 Montage des murs de plomb suplémentaires – juin 2014 : 1 cycle court réacteur ON de 1 mois test de bruit de fond de la casemate aménagée – 3 cycles jusqu’à fin 2014 Installation de STEREO : blindages et détecteur Tests de bruit de fond à chaque étape – 2 cycles en 2015 pour comissionning – 6 cycles d’avril 2015 à fin 2016 : Prise de données effectives – Début 2017 : changement du tube H6-H7

36 Shape analysis 11/6/2013 Labex ENIGMASS plenary meeting36

37 Sensitivity studies 11/6/2013 Labex ENIGMASS plenary meeting37

38 Efficiency & Energy resolution 11/6/2013 Labex ENIGMASS plenary meeting38

39 Efficiency & Energy resolution 11/6/2013 Labex ENIGMASS plenary meeting39


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